* Split out getLanguageData from character.[Ch] into its own files,

* Split out getLanguageData from character.[Ch] into its own files,
frnt_lang.[Ch]. Move all these functions into namespace frnt as
namespace charcter doesn't make much sense anymore.
* Associated changes to ControlCharacter and to FormCharacter.
* Use the same approach to internationalise the language names in the document
dialog.

git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@4087 a592a061-630c-0410-9148-cb99ea01b6c8